This would be the first suspect for problems. If you don't know the configuration of the virtual environment then you don't know that you have sufficient resources allocated to make any kind of comparison between the 32 bit physical server and the 64 bit virtual server.

This is a myth, plain and simple. I have been running high transaction databases in SQL Server virtualized for nearly 4 years now, and if the virtual environment is configured correctly, and has similar resource allocations to what a comparable physical environment would have, there is little to no difference in performance characteristics. Virtualization gets a bad wrap when to many guests are run on a physical host, resulting in oversubscription of the resources, or when insufficient resources for example Disk IO have been allocated when compared to what would have been done in a physical implementation.